Problem: Solve the following expression and give your answer as a fraction. $ 0.5 \times -0.78 \times \dfrac{5}{5} = {?} $
Solution: First get all of the numbers as simplified fractions. $ 0.5 = \dfrac{5}{10} = \dfrac{1}{2} $ $ -0.78 = -\dfrac{7.8}{10} = -\dfrac{39}{50} $ $ \dfrac{5}{5} = \dfrac{1}{1} $ Now we have: $ \dfrac{1}{2} \times -\dfrac{39}{50} \times \dfrac{1}{1} = {?} $ $ \phantom{ \dfrac{1}{2} \times -\dfrac{39}{50} \times \dfrac{1}{1}} = \dfrac{1 \times -39 \times 1} {2 \times 50 \times 1} $ $ \phantom{ \dfrac{1}{2} \times -\dfrac{39}{50} \times \dfrac{1}{1}} = -\dfrac{39}{100} $